On a map, Marib in Yemen and Vienna in Austria seem very far apart. But the space between the two, via Abu Dhabi, turns out to be too close for comfort. Indirect U.S. negotiations with Iran, over its nuclear program, in Vienna were already bogged down. Now the U.S. military has confirmed it participated in intercepting two Houthi ballistic missiles aimed at Al Dhafra Air Base near Abu Dhabi – home to the U.S. Air Force’s 380th Air Expeditionary Wing and 2,000 U.S. military personnel. In less than a month, a dramatic development in a local Arab conflict has rapidly gone regional and then, in effect, global, as intensifying attacks have erupted, shattering an 18-monthlong process of Middle East de-escalation.

The Houthis have launched this series of deadly missile attacks against the United Arab Emirates in retaliation for major setbacks in the battle around Marib, the economic hub of northern Yemen, due to the intervention of a potent UAE-backed Yemeni militia. Given that such sophisticated Houthi missiles are supplied by Iran, along with considerable evidence of crucial Hezbollah technical support, it will be difficult to ignore Iran’s involvement. And given that a major U.S. military headquarters and air wing have been directly attacked with these weapons, the direct line between Marib and Vienna, cutting through Abu Dhabi, is impossible to miss.

Why the Houthis are So Enraged

This series of Houthi missile attacks against the UAE began January 17, when missile and drone strikes destroyed several Emirati fuel tankers and killed at least three people and injured a number of others. The attacks were evidently retaliation for the dramatic recapture of key areas of Shabwa governorate in southern Yemen from Houthi forces by pro-government troops. This major reversal of fortunes was primarily due to the intervention of the extremely effective UAE-backed Giants Brigades.

While the UAE withdrew most of its own forces from Yemen in 2019, it retains a strong presence throughout the south and in other parts of the country. Indeed, the UAE’s role is one of the key reasons that, while the war pitting the Houthis versus the United Nations-recognized government and its backers in the Saudi-led coalition continues, that conflict has been effectively separated from the south, where the UAE is attempting to strike a balance between various southern factions while continuing a campaign against al-Qaeda and other militant groups.

The Giants Brigades’ intervention, undoubtedly conducted with the approval of the UAE, was facilitated by the ouster of the former governor of Shabwa, Mohammed Saleh bin Adio of the Islamist Islah Party, which is at loggerheads with Abu Dhabi. He was fired by Yemen’s president, Abd Rabbu Mansour Hadi, after unusually blunt criticism of the UAE’s role in the country and the increasing sense among powerful local tribes that he was unable to effectively lead the fight against the Houthi assault on the oil-rich governorate. With Adio out of the way and replaced by a new pro-UAE governor, Awad al-Awlaki, the powerful Giants Brigades swung into action with immediate results. By January 10, Awlaki declared Shabwa governorate “liberated” from the Houthis after the rebel forces were driven out of the Ain, Usailan, and Bayhan districts, which the Houthis had occupied earlier in a broader campaign to seize the neighboring governorate of Marib.

Oil-rich Shabwa and especially Marib are crucial to the Houthis as an economic hub. If the Houthis had been able to secure control of Shabwa, Marib would likely have been next, and that would have practically ended the Hadi government’s hopes of retaining a meaningful power base for national political influence. But the sudden reversal of fortunes engineered in a matter of days by the Giants Brigades means that Houthi control of crucial areas remains contested and that developments on the battlefield do not boil down to a series of inevitable victories by the Iran-backed forces.

It means, barring a significant reversal, that either the conflict in Yemen is going to continue into the foreseeable future with significant potential losses to the Houthis, or the rebels will have to engage, for the first time, in serious negotiations for a political resolution to the conflict with the Hadi government. Houthi participation in U.N.-brokered talks has thus far been pro forma and primarily reflected the group’s belief that continued fighting on the ground was more likely to produce additional gains.

The barrage of attacks aimed at the UAE and U.S. military facilities evinces the shock and frustration this abrupt and unexpected defeat has provoked among the Houthis. But what may have begun as an impulse to “bring the battle home” to the UAE by striking their opponents’ backers in their own country made the Yemen war more regional than ever. By attacking Al Dhafra Air Base, the Houthis have dragged in the United States. And by utilizing what are almost certainly Iranian-manufactured and supplied ballistic missiles, and quite possibly Hezbollah technical advisors, the Houthis have taken the battle over Shabwa global.

Washington, Tehran, and the Yemen War

The administration of President Joseph R. Biden Jr. has not yet given up on the indirect talks in Vienna aimed at reviving the 2015 Joint Comprehensive Plan of Action nuclear agreement with Iran that was effectively revoked in 2018 by former President Donald J. Trump. These talks have yielded few signs of progress, with U.S. officials suggesting they would not continue open-ended conversations for more than a few additional week. But it will be increasingly awkward to try to engage productively with Iran at this “decisive moment” when its close allies in Yemen are exporting their domestic war against the government by attacking not only an important U.S. partner but also a major U.S. military facility.

It’s extremely unlikely the exact nature of Iran’s (or Hezbollah’s) role in these attacks, beyond providing hardware, will be definitively determined. But given the escalation of the attacks over the past week to include Al Dhafra, forcing direct U.S. military involvement in Patriot anti-missile system interceptions of the ballistic missiles, there is no sign that Tehran has been uncomfortable with this Houthi intensification or has done anything to try to restrain it. Houthi boasting and bluster about the attacks strongly reinforce this impression.

Strategic Implications for Major Players

The Saudi-led coalition has responded with significant airstrikes in Houthi-held parts of Yemen that have inflicted significant damage on infrastructure and Houthi forces and caused numerous civilian deaths. Although the UAE has vowed a more substantial response, that will depend on various calculations, including the U.S. attitude, Iran’s potential reaction, and how significant a threat might be posed by additional Houthi missile attacks. Such strategic concerns might prompt the Emiratis to keep their primary focus on Shabwa and Marib. The continued advance of pro-government forces, especially the Giants Brigade, in Marib’s Juba and al-Abdiyah districts suggests that continuing this potent counteroffensive could be the most effective and least risky means to strike back against Houthi interests.

Beyond the Middle East, things get even more complicated. Given the importance of the Vienna talks to the Biden administration, Washington may try to play down any linkage between the Houthi attacks against the UAE and the negotiations. However, unless chief negotiator Robert Malley and his team can point to some results soon, anger over missile attacks against U.S. military facilities and personnel will inevitably combine with frustration over Iran’s apparent unwillingness to return to the deal on a straightforward compliance-for-compliance basis.

Indeed, in addition to a direct response to a dramatic setback on the ground in Yemen, the Houthi attacks against the UAE in part also reflect the ongoing willingness of Iran’s regional network of Arab militia groups to flex their muscles in highly provocative ways. Among other things this demonstrates a willingness and ability for Iran to boldly strike adversaries beneath the cover of at least semiplausible deniability for Tehran itself. Over the past two years, Iran has undoubtedly found the use of proxy strikes against adversaries an effective tool of leverage with very low, if any, costs – with the notable exception of the January 2020 U.S. drone strike that killed Major General Qassim Suleimani and Iraqi militia leader Abu Mahdi al-Muhandis. The overall pattern, however, suggests that Iran continues to view such proxy attacks as a major tool of statecraft, power projection, and even positioning for negotiations.

Finally, these attacks are an alarming reminder of how fragile strategic relations in the Middle East remain despite the past 18 months or more of significant de-escalation between major regional actors. Indeed, among the most dramatic of these budding rapprochements has been between the UAE and Iran. This process reached a high point in early December 2021 when the UAE’s national security advisor, Tahnoun bin Zayed al-Nahyan, visited Tehran and invited Iranian President Ebrahim Raisi to make an official state visit to the UAE this year. Both parties have appeared keen on improving relations. But it will, of course, be extremely difficult for a Raisi state visit to Abu Dhabi to take place as long as Iranian missiles are striking targets inside the UAE.

Moreover, the sudden eruption of regional violence directly out of dramatic battlefield developments in Yemen demonstrates that what takes place in a relatively remote Middle Eastern conflict doesn’t necessarily stay there. In a matter of days, a major regional player can be pulled back into the Yemen conflict from which it is trying to disengage and diplomacy with global stakes can be rendered riskier and more complex than ever. The sudden impact of conflict is still readily capable of producing a wrinkled strategic and political landscape in which Marib, Abu Dhabi, and Vienna are functionally in the same neighborhood.